Some chests require the items inside to be stolen form the chest so a thief has its advantage.

You can only steal from other players in Felucca and at 60+ skill and being in the thieves guild. Once that character is 40 hours old in-game and you have 60+ stealing, go to a thief guildmaster/mistress and say <name> join. once in you can steal from other players.

for each stone of weight from items is 10 skill required. you want to steal a 8 stone item you need 80+ stealing